The present invention relates to vehicle flashers and, in particular, to apparatus for providing a self cancelling flashing signal. In operating a vehicle such as a bicycle, motorcycle or automobile, it is often necessary to give a warning signal by flashing a light. Such flashing, if done manually, occupies the drivers hands and distracts him from controlling his vehicle. This situation is exacerbated by the fact that the driver may wish to simultaneously sound the horn while he flashes his lights.
It is known to provide a turn signal from an electronic circuit that flashes the turn signal indicator for a predetermined time before cancelling the flashing operation. Because they concern turn signals, these known circuits fail to recognize some of the advantage that can be built into a more general system signaling. Known flashing circuits have included a pair of timing circuits. The circuits are arranged so that both timers, however, must be operational before any response is delivered to the light. Thus there is no opportunity to signal should only one circuit be operational. This defeats any failsafe operation.
Also known flashing circuits have not been arranged to require that an upstream interval circuit be successfully operated before the higher frequency flashing circuit begins operating. Instead, known circuits have triggered a high speed cycling circuit directly from a manual switch to render the high speed cycling circuit self-perpetuating. This self-perpetuating circuit requires the successful operation of another timer circuit to terminate the flashing. Such circuits fail to prevent flashing at the outset should the long term interval timer be defective. Accordingly, there is a need for an improved and relatively simple circuit for flashing a warning light in a reliable and preferably failsafe manner.